Condensed Consolidated Statements of Equity (Unaudited) (USD $) In Thousands	Total	Common Stock Voting Shares Issued	Common Stock Non-Voting Shares Issued	Paid-In Capital	Retained Earnings/ (Accumulated Deficit)	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Beginning balance at Dec. 31, 2009	$ 431,991	$ 204	$ 95	$ 1,013,790	$ (519,220)	$ (62,878)	$ 0
Beginning balance, shares at Dec. 31, 2009		20,391	9,506
Net income (loss)	487,341				486,846		495
Other comprehensive loss	(32,995)					(32,995)
Comprehensive income	454,346
Exercise of stock options, shares		547
Exercise of stock options	13,995	5		13,990
Shares surrendered to fund withholding taxes, shares		(13)
Shares surrendered to fund withholding taxes	(2,477)			(2,477)
Tax benefit associated with exercise of stock options	412			412
Stock based compensation	2,548			2,548
Contribution by noncontrolling interest	134						134
Ending balance at Dec. 31, 2010	900,949	209	95	1,028,263	(32,374)	(95,873)	629
Ending balance, shares at Dec. 31, 2010		20,925	9,506
Net income (loss)	97,421				97,152		269
Other comprehensive loss	(5,110)					(5,110)
Comprehensive income	92,311
Exercise of stock options, shares		277
Exercise of stock options	447	3		444
Shares surrendered to fund withholding taxes	(16,765)			(16,765)
Tax benefit associated with exercise of stock options	1,361			1,361
Stock based compensation	554			554
Ending balance at Jun. 30, 2011	$ 978,857	$ 212	$ 95	$ 1,013,857	$ 64,778	$ (100,983)	$ 898
Ending balance, shares at Jun. 30, 2011		21,202	9,506